System and method for reconfigurable metasurface sub reflector
A reconfigurable metasurface sub reflector comprises an array of cell units. Each sub unit is formed of two sub-unit cells formed with at least two conducting layers separated by a dielectric substrate. One conducting layer has, in each of the sub-unit cells, two parallel strips connected by a varactor and the other conducting layer serves as a ground layer. Setting the reverse biasing for each of the varactors controls the azimuth and elevation of reflection from the reconfigurable metasurface sub reflector.
1. A unit cell for use in re-configurable metasurface sub reflector, the unit cell comprising:
two sub-unit cells disposed next to each-other and sharing a common center line, each of the sub-unit cells has a length P and a width W;
at least two conducting layers disposed parallel to each other;
at least one dielectric layer, disposed between the at least two conductive layers;
wherein each of the sub-unit cells comprise, formed in a first conducting layer of the at least two conducting layers:
a first strip disposed distal from the center line; and
a second strip disposed proximal to the center line,
wherein the first and the second strips of both sub-unit cells are formed as thin strip with their longitudinal dimension parallel to the center line and to each-other; and
a voltage controlled capacitor disposed between the first and the second strips of both sub-unit cells,
wherein the distance between the second strip of a first sub-unit cell and the second strip of a second sub-unit cell is approximately 0.07 of the wavelength of the operative frequency of the unit cell.
2. The unit cell of claim 1 , wherein a second of the at least two conducting layers is adapted to function as a ground layer for the unit cell and the first conducting layer is adapted to be connected to voltage for controlling the capacitance of the voltage controlled capacitor.
3. The unit cell of claim 1 wherein the length (P) of each of the sub-unit cells is no more than 0.33 of the wavelength of the operative frequency of the unit cell and the width (W) of each of the sub-unit cells no more than 0.2 of the wavelength of the operative frequency of the unit cell.
4. The unit cell of claim 1 wherein the distance between the first strip and the second strip of the first and the second sub-unit cells is approximately 0.09 of the wavelength of the operative frequency of the unit cell.
5. The unit cell of claim 1 further comprising a second dielectric layer disposed on the free face of the second conducting layer and a third conducting layer disposed on the other side of the second dielectric layer, the third conducting layer having formed therein, a first pad connected a first strip of the first sub-unit cell and a second pad connected to the and a second pad connected to the first strip of the second sub-unit cell.
6. A re-configurable metasurface sub reflector comprising plurality of metasurface unit cells, the sub reflector comprising:
an array of N×M unit cells, each of the unit cells comprising:
two sub-unit cells disposed next to each-other and sharing a common center line, each of the sub-unit cells has a length P and a width W;
at least two conducting layers disposed parallel to each other;
at least one dielectric layer, disposed between the at least two conductive layers;
wherein each of the sub-unit cells comprise, formed in a first conducting layer of the at least two conducting layers:
a first strip disposed distal from the center line; and
a second strip disposed proximal to the center line,
wherein the first and the second strips of both sub-unit cells are formed as thin strip with their longitudinal dimension parallel to the center line and to each-other; and
a voltage controlled capacitor disposed between the first and the second strips of both sub-unit cells,
wherein the distance between the second strip of a first sub-unit cell and the second strip of a second sub-unit cell is approximately 0.07 of the wavelength of the operative frequency of the unit cell.
7. The re-configurable metasurface sub reflector of claim 6 , wherein a second of the at least two conducting layers is adapted to function as a ground layer for the unit cell and the first conducting layer is adapted to be connected to voltage for controlling the capacitance of the voltage controlled capacitor.
8. The re-configurable metasurface sub reflector of claim 6 , wherein the length (P) of each of the sub-unit cells is no more than 0.33 of the wavelength of the operative frequency of the unit cell and the width (W) of each of the sub-unit cells no more than 0.2 of the wavelength of the operative frequency of the unit cell.
9. The re-configurable metasurface sub reflector of claim 7 wherein the distance between the first strip and the second strip of the first and the second sub-unit cells is approximately 0.09 of the wavelength of the operative frequency of the unit cell.
10. The re-configurable metasurface sub reflector of claim 6 further comprising a second dielectric layer disposed on the free face of the second conducting layer and a third conducting layer disposed on the other side of the second dielectric layer, the third conducting layer having formed therein, a first pad connected a first strip of the first sub-unit cell and a second pad connected to the and a second pad connected to the first strip of the second sub-unit cell.
11. A method for controlling the direction of reflection of radiation of electromagnetic waves from a re-configurable metasurface sub reflector comprising:
providing a re-configurable metasurface sub reflector comprising plurality of metasurface unit cells, the sub reflector comprising:
an array of N×M unit cells, each of the unit cells comprising:
two sub-unit cells disposed next to each-other and sharing a common center line, each of the sub-unit cells has a length P and a width W;
at least two conducting layers disposed parallel to each other;
at least one dielectric layer, disposed between the at least two conductive layers;
wherein each of the sub-unit cells comprise, formed in a first conducting layer of the at least two conducting layers:
a first strip disposed distal from the center line; and
a second strip disposed proximal to the center line,
wherein the first and the second strips of both sub-unit cells are formed as thin strip with their longitudinal dimension parallel to the center line and to each-other; and
a voltage controlled capacitor disposed between the first and the second strips of both sub-unit cells,
wherein the distance between the second strip of a first sub-unit cell and the second strip of a second sub-unit cell is approximately 0.07 of the wavelength of the operative frequency of the unit cell; and
providing reverse voltage to each of the unit cells of the metasurface sub reflector according to control the direction of reflection in azimuth and in elevation.
12. The method of claim 11 wherein a second of the at least two conducting layers is adapted to function as a ground layer for the unit cell and the first conducting layer is adapted to be connected to voltage for controlling the capacitance of the voltage controlled capacitor.
13. The method of claim 11 , wherein the length (P) of each of the sub-unit cells is no more than 0.33 of the wavelength of the operative frequency of the unit cell and the width (W) of each of the sub-unit cells no more than 0.2 of the wavelength of the operative frequency of the unit cell.
14. The method of claim 11 wherein the distance between the first strip and the second strip of the first and the second sub-unit cells is approximately 0.09 of the wavelength of the operative frequency of the unit cell.